Vehicle-suspension means



VEHICLE-SUSPENSION MEANS Filed Dec. V1, 1958 2 sheets-sheet 1 f@ a 5M aHMM /70 INVENTORS.

BY fr' ,60 m

NOV. 13, 1962 H, Q HARBERS ETAL l 3,063,703

VEHICLE-SUSPENSION MEANS Filed Deo. l, 1958 2 Sheets-Sheet 2 UnitedStates Patent() fornia Filed Dee. 1, 1958, Ser. No. 777,472 14 Claims.(Cl. 267-65) This invention relates generally to vehicle-suspensionmeans and relates more particularly to suspension means for vehicleshaving widely varying-load conditions.

While the invention has particular utility in connection with thesuspension means for trailers and semi-trailers which may be used with aheavy load or with little or no load, and as shown and described in suchconnection, it is to be understood that its utility is not confinedthereto.

A dicult problem is involved in providing suspension means for vehicles,such as trailer and semi-trailers, which are usually operated eitherwith a heavy load or with little or no load, that is, empty. When werefer to the vehicle as being empty, it is to be understood that theremay be no load in the vehicle or there may be Va relatively light load.

Should leaf springs, or the like, be used, which are strong enough toproperly support the vehicle when loaded, such springs will be too stiiffor the empty vehicle and the ride thereof will be extremely rough.Should the springs have the proper characteristics to give good ridingqualities for an empty vehicle they will not supply proper support forthe heavily loaded vehicle.

r ICC Patented Nov. 13, 1962 this example, skilled persons willunderstand that many variations may be made without departing from theprinciple disclosed and we contemplate the employment of any structures,arrangements, or modes of operation, that are properly within the sco-peof the appended claims.

Referring to the drawings, which are for illustrative purposes only:

FIG. l is a side elevational view of a vehicle-suspension meansembodying the present invention.

FIG. 2 is a sectional View taken on line 2 2 of FIG. l.

FIG. 3 is a plan view of one side of the suspension means.

FIG. 4 is a schematic view of the pneumatic system of the apparatus, and

FIG. 5 is an enlarged diagrammatic `sectional view of one ofthe controlvalves.

Referring more particularly to the drawings, there is shown a portion ofa vehicle frame, indicated generally at 1i?, having a hollow sub-frame,indicated generally at l2. The sub-frame is rectangular in form and issecured to the frame l0 of the vehicle by any suitable well-known means,such as welding or the like', not shown. The subfrarne 12 has sidemembers-12a and end members 12b, the latter being welded, as at 12C, tothe ends of the members 12a and .seal said ends. There is also a centraltransverse member 12d having its ends welded to the It is, therefore, apurpose of this invention to provide suspension means for vehicles ofthe above character which will solve the problem of giving proper ridecharacteristics for such vehicles under both loaded and empty operatingconditions.

The invention contemplates an arrangement using both leaf springs andair-cushioning means. The springs, among other things, control thelateral alignment of the axle, take the brake torque, and give thetrailer its ride. The springs in the present arrangement provide supportfor the vehicle when empty, While the air-cushioning means cooperateswith the springs to support the vehicle when loaded.

Another purpose of the invention is to provide vehiclesuspension meansof this character wherein the air cushion or spring means isautomatically brought into operation by the weight of vehicle load.Still another' purpose of the invention is to provide aircushioningmeans including a reservoir having a relatively large cushioningcapacity.

A further purpose of the invention is to provide a reservoir of suchsize and capacity as to create the proper oscillating frequency of thesuspension means. The size of the reservoir is calculated in relation tothe motion and weight of the load the vehicle is designed to carry.

Another purpose of the invention is to provide in apparatus of thischaracter, a reservoir which constitutes partof the sub-frame of thevehicle.

Still another purpose of the invention is to provide suspension meanswherein the air-cushioning means is manually released.

A further purpose of the invention is to provide vehiclesuspension meansthat is simple in construction and operation.

A still further purpose of the invention is to provide vehiclesuspension means that is relatively inexpensive to manufacture and toservice.

The characteristics and advantages of the invention are furtherysufficiently referred to in connection with the following detaileddescription of the accompanying drawings which represent one embodiment.After considering respective 'members 12a. The members 12a serve asfluid reservoirs for the pneumatic system as will be described moreparticularly hereinafter.

While the vehicle may have a plurality of axles, only one is shown andindicated at 16.v Adjacent to each end of said axle is a leaf spring 18having the central porltion secured to said axle by means of the usualspring plate 20 and U-shaped tie bolts 22 having the usual nuts 24 atthe ends thereof.v One end of each spring 18, shown as the forward end,has an end portion secured in a spring hanger, indicated generally at26'. The hanger 26 is of known character and comprises an upper member28 which is secured to the sub-frame 12 by any suitable means, such aswelding or the like, and a lower member or cap 30 is secured to thelower end of the member 28 by means of bolts 32, and the forward endportion of the spring 18 is held in a fixed position againstlongitudinal movement vby said hanger. The rear end portion of thespring 18 is operably received in a spring guide 36 which is secured tothe rear of the sub-frame by welding or other suitable means. The rearend of the spring 18 is adapted to be slidably held in the guide 36,there being the usual'bolt 38 beneath the spring and a wall member 40above the spring. The rear end portion of the spring is, therefore, freeto move longitudinally in the usual manner but is held against lateralmovement and one of the leaves of said spring is provided with a downfturned end 42 to limit inward movement of said spring and thus preventinadvertent separation of the spring from the guide 36.

As stated above, there is a spring 18 at each side of each of thevehicle axles and said springs 18 have the proper ride characteristicsfor the vehicle when unloaded, but there is means associated with eachspring for providing supplemental suspension when the vehicle is loadedand said means is pneumatic in character.

Between the central portion of each spring and the ad jacent portion ofthe axle is clamped a plate 46, to the under side of which and at eachend is secured by means of screws 48 a pneumatic motor device 50. Thesedevices are of known character and will be but briey described. Each ofthese motor devices includes a cylindrical housing 52 with a top cover54. At the lower end of the cylindrical housing 52 there is a reduceddiameter portion 56 which has a relatively large opening 58 thereindefined by a iiange 69 formed by turning inwardly a lower end portion ofthe reduced diameter-portion 56.

Within the device 50 there is a cup-shaped member 64 which is secured tothe flange 60 by means of rivets 66. At its upper end the cup-shapedmember 64 has an outwardly turned edge portion 68 which receives a Ibead70 about the upper marginal edge of a flexible diaphragm 72. The bead 70is held against the shoulder 74 formed at the junction of the lower endof the cylindrical housing and the reduced diameter portion 56 thereof.`Within the cup-shaped member 6'4 is a diaphragm assembly which includeslsaid diaphragm 72 and a cupshaped diaphragm retainer 76 which has aninwardly formed recess 78 at the bottom for reception of a bead 80 ofthe diaphragm about the lower edge thereof. Secured to the under side ofthe retainer 76 is a reinforcing plate 82. secured to the retainer 76and provided with an upturned marginal edge 84, the bead 80 beingsecurely clamped between the retainer 76 and the plate 82.

Axially disposed in the device 50 is a rod 86 the lower end of which issecured to the diaphragm assembly by any suitable well-known means suchas a bolt 88 and said rod extends upwardly through an opening providedtherefor in the cover 54. The diaphragm assembly is urged downwardly bymeans of a spring 90 operably disposed about the rod 86 and reactingagainst the cover 54 and a spring retainer 92 resting on the bottom ofthe diaphragm retainer 76.

The device 50 thus has a pressure chamber 77 below and at the outersides of the diaphragm assembly and a chamber 79 at the opposite sidethereof, chamber 79 being freely vented to atmosphere by means of vents,not shown.

Plate 46 hasan upturned outer-edge "portion 96 which moves upwardly vtobe Ydisposed at the outer side of the adjacent part ofi the sub-frame 12when the vehicle is loaded. The rod 86 extends upwardly through alignedopenings provided therefor in the. cover 54 and the 'rod 86 and carriesa conical head 98 at the upper end thereof adapted to be received in acorrespondingly-shaped rece'ss 100 in a socket 102 secured, by weldingor therlike, to the `underside of a plate 104 which, inturn, is secured,.by welding or 4other suitable means, to the underside 'of ther adjacentsub-'frame member 12a.

rIhe pressure chambers 77 of the pneumatic devices 50 for thespriug 18are connected together by conduits 112 land 114, said conduits beingconnectedat their junction by means of a T 116 which, in turn', has 'aconnection 118 leading to aT 120.V T 1,20 has a connection 122 Vwith theadjacent reservoir 12a of the sub-frame 12 said reservoirs ,12akbeingindependent of4 each other and serving as additional pneumaticcushioningv for the devices 50 with which they lare connected. The Talso has a connection 172,4 with a port V126Y of a button bleeder valve128 of well known type. Port 12`6`is; located midway between the ends`cfa cylinderhlt! of the yalve '128jand said cylinder is providedY withan inlet'port 132 which, as yiewed in FIG. 5, is spaced longitudinallyto the right relative to port, 126 and is connected withl a check valve1,34 b y means of'a conduit 136. The valve 1 28 fork the opposite springof axle 16 is similarly constructed and has asimilarconnection withvthefcheck valve 134. Checlcvalves 13.4. are connected: tO- source ofpressure, such as ay pressure storage tanl; 139; by means of a conduit140 and branch 'conduits 142, the; latter leading to said check valves.Means for supplyin'gthe tahk139. is provided and maybe the usual pump Pfor the air-brake system of.'thevehicle. i Y Y Y 'Each valve 1,278is'providedwithan exhaust port 144`t'o atmosphere spaced longitudinallyto `the left ofthe port 126, anda spool valvgfgenerally indicated `atl14t'S,`is` dis;- posedwithin the cylinder 130'a'nd' Vslidable therein.'Spool valve 146 comprises va pair of `spoolsg148and 1750 axially spacedapart Yand connected A(by a l reduced diameter/portion 152. The valvev146'is shorter than the cylinder 130 andthereare pressure connections1'54 and lf'between the inlet 132 and the respective ends of thecylinder 130. The cylinder has the ends closed by respective end walls158 and 160 which are provided with tapped openings 162 and 164. Theopening 162 is provided with a button bleeder 166 which is threaded intothe opening 162 and has a bleed vent 168 therein controlled by a valvemember 170. When said valve member 170 is in its outer position thebleed vent 168 is closed and when said button 170 is pushed inwardlysaid vent is opened, the button bleeder being normally closed. Theopposite end of the valve 128 is provided with a remote-control buttonbleeder 174 having -a connection 176 with a fixture 178 secured in thetapped opening 164. The button bleeder 174 is provided with a bleed vent180 and a button valve 182 for controlling same. Normally the buttonvalve 182 is in its outer position whereat the bleed is closed but whenpushed inwardly it opens the bleed vent 180. When the button bleed ventsat the ends of the valve 128 are closed the pressures at the ends of thespool valve member 146 are in balance.

Spring plate 2t) has an upstanding valve-actuating arm 186 which issecured to said plate by means of a screw 188. The upper end of the arm186 is curved at 190 and said arm is adapted to move upwardly to engagethe button 170 of the bleeder 166, the valve 128 being secured` byscrews 192, or the like, to the adjacent portion of the sub-frame sothat the button 170 is in the path of movement of the arm 186 and willbe forced inwardly by said arm when the vehicle frame is moveddownwardly by the weight of the load. It is to be noted that when thevehicle is loaded the button 170 is engaged by said arm adjacent thecenter thereof so that the valve will be maintained open even thoughthere are oscillatory movements which vary the spacing between the axleand supporting frame. When the button bleeder is in the open positionair pressure is relieved in the adjacent end of the cylinder so thatpressure at the opposite end will force the spool valve 146 rightwardlyas viewed in FIG. 4 and connect the inlet port 132 with the port 126 sothat pressure iluidis applied to the under side of the diaphragms ofthemotor devices 50. This pressure causes the diaphragm to move upwardlyand cause the conical head 98 to enter the conical socket 100.

As both of the devices 50 at both ends of the axle are actuated when thevehicle is loaded, supplemental pneumatic suspension is thereforeprovided for the vehicle under such condition. This pneumatic suspensionadded to the springs 18 provides the `proper suspension and ride for thevehicle when loaded.

Whenthe vehicle is unloaded the frame is raised by the springs and thepneumatic suspension to effect clos-l ing of the button bleeder 166.Pressure at opposite ends of the spool valve 146 is again equalized andin order to' disconnect the pneumatic suspension the button bleeder' 174is pushed inwardly to relieve the pressure in the left endof thecylinder 130 so that the pressure applied to thel opposite end of thespool valve 146 will cause same to move to the left to close the port132 and open the port 144, thus relieving the air pressure within thepneumatic motor devices 50. The Vsprings 90 of said devices will thenmove the rods 86 to their lower positions whereat the heads 98 are outof engagement with the sockets 102..

It is believed that it will be apparent that each side ofthel vehicle ateach axle is independently supported by the suspension means whichcomprises both the springs and the pneumaticrmechanism.

Resilient rubber bumpers V194 of the usual well-known character areprovided above the axles` it is thought that the invention and many ofits attendant advantages will be understood from the foregoingdescription and'it is thought that it will be apparent that variouschanges may be made in the form, construction and arrangement of theparts of the invention without departing from the spirit and scopethereof or sacrificing all of its material advantages, the embodimenthereinbefore described being merely a preferred one.

What we claim is:

l. Vehicle-suspension means, comprising: a sub-frame having side and endmembers, two of said members being hollow with the interiors thereofindependent of each other; a transverse axle beneath said sub-frame; aleaf spring at each end of the axle; means iixedly securing the frontend of each spring to the adjacent portion of the sub-frame; a mount foreach spring adjacent the opposite end for supporting said spring endwhile permitting longitudinal movement thereof, said mounts beingsecured to the sub-frame; means at the rear end of each springpreventing same from inadvertent separation from the respective mount; apair of pneumatic motor devices adjacent each end of the axle, one ofsaid devices being forwardly of the axle and the other rearwardlythereof; means securing each pair of motor devices to the axle; each ofsaid motor devices comprising a housing with a diaphragm assemblytherein, there being a pressure chamber at one side of the diaphragm anda chamber vented to atmosphere at the other side; a rod axially securedto the diaphragm assembly and extending upwardly of the upper end o thedevice; a conical head on the rod; a socket for each of said devicessecured to the adjacent portion of the sub-frame and having a socketopening -acing said head and adapted to receive same when the -rod ismoved upwardly by pressure in the pressure chamber; meansinterconnecting the pressure chambers of the motor devices at therespective ends of the axle and with one of said hollow sub-framemembers; a source of pressure uid for said motor devices; conduit meansconnecting said source of pressure with said motor devices; a checkvalve in said conduit means for each pair of motor devices; a controlvalve for each pair of motor devices, connected into the conduit meansthereto, said valve being secured to the sub-frame, each of said controlvalves having a valve member adapted to be actuated between a positionconnecting the source of pressure fluid with a pair of motor devices andanother position connecting the pressure chambers of said devices toatmosphere; means for said control valve adapted, when actuated, toeffect movement of said valve member to the position whereat said sourceof pressure fluid is connected with the pressure chambers of said pairof pneumaticmotor devices; an arm connected to each spring and adaptedto actuate said valve-control member when the vehicle is loaded andthere is relative movement between the axle and sub-frame to therebyconnect the source of pressure fluid with the pressure chambers of saidpair of pneumatic-motor devices; and second control means for said valveadapted to be manually actuated and when actuatedto cause the valvemember to connect the pressure chambers of said pair of pneumatic-motordevices with atmosphere.

2. Vehicle-suspension means, comprising: a sub-frame having side and endmembers, two of said members comprising iluid pressure reservoirs, saidreservoirs being independent of each other; a transverse axle; a leafspring secured to the axle adjacent the respective ends thereof; meansoperably securing the springs to the sub-frame; a pair ofpneumatic-motor devices secured to the axle adjacent each end thereof;one of said devices being forwardly of the axle and the other rearwardlythereof; each of said motor devices having a uid pressure chamber, adiaphragm assembly subjected on one side to the pressure in saidchamber; a rod secured to the diaphragm assembly and extending upwardlyof the upper end of the device; a socket secured to the adjacent portionof the subframe and having a socket opening aligned with said rod andadapted to receive the upper end thereof when the rod is moved upwardlyby pressure in the pressure charnber; means interconnecting the pressurechambers of each pair of motor devices and with one of said reservoirs;a source of pressure fluid for said motor devices; a valve for each pairof motor devices secured to the sub-frame, each of said valves havingtwo operative positions, one

connecting the source of pressure fluid with the pressure chamber of itsrespective pairs of motor devices and the other position connecting saidpressure chambers to atmosphere; respective means for actuating saidvalves to effect connection of said source of pressure uid with thepressure chambers of respective pairs of pneumatic-motor devices whenthe vehicle is loaded and there is a predetermined relative movementbetween the axle and subframe; and manually-operable means forrespective valves for actuating same to said other position to connectthe pressure chambers of respective pairs of pneumatic motor deviceswith atmosphere.

3. In suspension means for vehicles having a frame: a transverse axle: aleaf spring adjacent each end of the axle` and centrally mountedthereto; means operably mounting said springs to the vehicle frame;pneumaticsuspension means including a set of pneumatic-motor devicessecured to each end of said axle and at opposite sides thereof; each ofsaid motor devices including a pressure chamber, one wall of whichcomprises a flexible diaphragm; a connecting member carried by eachdiaphragm; a receiving member for each connecting member, said receivingmembers being carried by the vehicle frame and being aligned withrespective connecting members, said connecting members beingdisconnected from the receiving members when the pneumatic motor devicesare deenergized; means interconnecting the pressure chambers of each setof motor devices; means defining a reservoir for each set of motordevices; means connecting the pressure chambers of each set of motordevices with a respective resevoir, a source of pressure iluid; valvescontrolling the pressure uid to respective sets of motor devices; meanscarried by said axle for controlling respective valves to connect saidsource of pressure fluid with the pressure chambers of respective setsof motor devices Iwhen there is a pre-determined relative movement ofthe axle and frame toward each other to thereby connect the source ofpressure liuid with the pressure chambers of the pneumatic motors toenergize said motor devices and to cause the diaphragms thereof to movethe respective connecting members into engagement with the receivingmembers; means for relieving the pressure in said chambers; and meansfor moving said connecting members lfrom engagement with said receivingmembers.

4. In suspension means for a vehicle having a frame structure: atransverse axle structure; a leaf spring adjacent each end of the axlestructure and centrally secured thereon; means operably mounting saidsprings to the yvehicle frame structure; pneumatic-suspension meansincluding a set of pneumatic motor devices at each side of the vehicleand secured to one of said structures; each of said motor devicesincluding ia pressure chamber, one wall of which comprises a flexiblediaphragm; a connecting member carried by each diaphragm; a receivingmember for each connecting member, said receiving members being carriedby the other structure and being aligned with respective connectingmembers, said connecting members being disconnected from said receivingmembers when the pneumatic motor devices are deenergized; meansinterconnecting the pressure chambers of each set of motor devices;means defining a reservoir for each set of motor devices; meansconnecting the pressure chambers of each set of motor `devices with aVrespective reservoir; ya source of pressure fluid; valves controllingthe pressure luid to respective sets of motor devices; means carried byone of said structures for controlling respective valves to connect saidsource of pressure fluid with the pressure chambers of respective setsof motor devices when there is a predetermined relative movement of theaxle and frame structures toward each other to thereby connect thesource of pressure fluid with the pressure chambers of the pneumaticmotors to energize said motor devices land to cause the diaphragmsthereof to move the respective connecting members into engagement withthe receiving members; means for relieving the pressure posite end forsupporting said spring while permitting limited longitudinal movementthereof, said mounts being secured -to the sub-frame; a pair ofpneumatic motor devices for each spring, one of said devices -beingforwardly of the axle and the other rearwardly thereof; meanssecuringreach pair of motor devices to the respective ends of the axle;each of said motor devices having a movablewall assembly defining apressure chamber; a rod axially secured lto the diaphragmn assembly andextending upwardly of the upper end ofthe device; a socket secured tothe adjacent, portion of the sub-frame and having a -`socket yopeningfacing the upper free end of said rod and adapted to receive same whenthe rod is moved upwardly by pressure in the pressure chamber; meansinterconnecting the pressure chambers of the motor devices at therespective ends of the axle and with one of said hollowsub-framemembers; a source of pressure Huid; a valve for each pair of motordevices, said Ivalve being secured to the sub-frame, each of said valveshaving a valve member adapted to be 4actuated between the positionconnecting the source of pressure liuid with the actuators at one end ofthe axle and another position connecting the pressure chambers 'of saiddevicesy to atmosphere; means for said valve adapted when actu-ated toeifect connection of said source of Ypressure liuid with the pressurechambers of said pneumatic motors; a valve actuating arm connected toeach spring and adaptedto actuate the valve control member when thevehicle `is loaded and there is relative movement toward each other ofthe axle andsub-frame to thereby connect the source of pressure fluidwith the Vpressure chambers of the pneumatic motors; and second controlmeans for said valve adapted toV be manually actuated Vand whenactuatedwill ycause the valve member to connect 4the pressure chambers of saidpneumatic motors with atmosphere.

6. lSuspension ymeans yfor a vehicle having a frame, comprising: asub-frame adapted to be secured to said vehicle frame, said sub-framehaving side and end members, two of lsaid members being hollowwith theinteriors thereof independent of each other; a transverse axle; a leafspring at each end of the axle; means lixedly securing the front end ofeach spring to the adjacent portion of the sub-frame; =a mount for eachspring adjacent the opposite end for supporting said spring whilepermitting limited longitudinal movement thereof, said mounts beingsecured to the sub-frame; a pair of pneumatic-motor devices for eachspring, one of said devices being Vforwardly of the axle and the otherrearwardly thereof; means securing eachV pair of motor devices to therespective ends of the axle; each of said motor devices having amovablewall assembly delining a pressure chamber; a rod -axially securedto the diaphragm assembly and extending upwardly of the upper end of thedevice; a socket secured to the adjacentportion of the sub-frame andhaving a socket opening facing the upper free end of said rod and`adapted to receive same when the rod is moved upwardly by :pressure inthe pressure chamber; means interconnecting the pressure chambers of themotor devices at the respective ends of the axle and with one of Vsaidhollow subframe members; 'a source of pressure huid; a valve for eachpair of motor devices, said'valve being secured to the sub-frame, eachAof said valvesfhaving a valve member adapted to be actuated between theposition connecting -tliesource of. pressure uid with the actuators atone end of the axle and another position connecting the pressurechambers of said devices to atmosphere; means for said valve adaptedwhen actuated to effect connection of said source of pressure fluid withthepressure chambers of said pneumatic motors; and a valve-actuatingyarm connected to each spring and adapted to actuate the valve controlmember when the vehicle is loaded and there is relative movement towardeach other of the axle land sub-frame to thereby connect the source ofpressure liu-id with the pressure chambers of the-pneumatic motors.

7. ln suspension means for a vehicle: ya sub-frame structure adapted tobe secured to the frame of said vehicle, said sub-frame including a pairof hollow members each comprising :a pneumatic reservoir, an axlestructure therefor including an-axle extending transversely of saidsub-frame structure; pneumatic-suspension means including a pair ofpneumatic-motor devices secured to each said of said axle structure, oneof said devices at each side being forwardly and the other rearwardly ofthe axle, each device having a pressure chamber defined at Vone side bya-movable wall; conduit means interconnecting the pressure chambers ofeach pair of devices and one of said reservoirs; valve means for eachpair of devices for controlling pressure iiuid thereto and to therespective reservoirs; means for independently actuating said valves forthe application of pressure iiuid to the .pressure chambers ofrespective pairs Vof devices when 'connected between said frame and axlestructure; pneumatic-suspension means including a pair of pneumaticmotordevices secured to each side of Vsaid axle structure and cooperatingwith said leaf spring means to support a load carried by said framestructure, one of said devices at each side being forwardly and theother rearwardly of the axle and each device having a pressure chamberprovided with a movable wall and including supplemental 'load supportingmeans operatively connected to vsaid movable wall exteriorly of saidpressure chamber; conduit means opening into the pressure lchambers ofeach pair of devices and including valve means for each pair of devicescontrolling the flow of pressure 'fluid thereto; means Yfor actuatingsaid valves to supply pressure fluid to the pressure chambers ofrespective pairs of said devices upon a predetermined movement of saidaxle and 4frame structures toward vreach other, the admitted fluid beingeffective to actuate said movable walls to extend said supplemental loadsupporting means and render said devices effective to provide pneumaticlconnection between said devices and said frame.

l0. ln suspension means for a vehicle having a frame structuref Yan axlestructure including an Vaxle extending transversely of said framestructure; leaf spring means connected between said frame and axlestructures; pneu- Amatic-suspension means including a pair of pneumatic-Vmotor devices secured to each side of said axle structure and beingcooperable with said leaf spring means to support a load carried by saidframe structure, one of said devices/at each side being Yforwardlyandthe other being rearwardly of the axle and in communication with oneanother and each device having a pressure chamber proindependentlyactuating said valvesfor the application of pressure tiuid to thepressure chambers of respective pairs of said devices upon apredetermined movement of said axle and frame structures toward eachother to thereby actuate said movable walls, and means operablyassociated with said movable wall to provide supplemental pneumaticconnection means between said devices and said frame when pressurizedair is supplied to said pressure chambers.

ll. In suspension means for a vehicle having a frame structure: an axlestructure including an axle extending transversely of said framestructure; leaf spring means connected between either side of said framestructure and said axle structure; pneumatic-suspension means includinga pair of pneumatic-motor devices in air flow communication with oneanother and secured to each side of said axle structure, one of saiddevices at each side being forwardly and the other being rearwardly ofthe axle, each device having a pressure chamber delined at one side by amovable wall; conduit means opening into the pressure chambers of eachpair of devices and including valve means for each pair of devicescontrolling the flow of pressure uid thereto; means for actuating saidvalves for the application of pressure iluid to the pressure chambers ofrespective pairs of said devices upon a predetermined movement of saidframe and axle structures toward each other to thereby simultaneouslyactuate said movable Walls by said uid and render said devices effectiveto provide load-supporting pneumatic connection between said devices andsaid frame and supplement said leaf spring means in supporting a loadcarried by said frame structure.

12. In suspension means for a vehicle having a frame structure: an axlestructure including an axle extending transversely of said framestructure; leaf spring means connected between either side of said framestructure and said axle structure; pneumatic-suspension means includinga pair of pneumatic-motor devices in air flow communication with oneanother and secured to each side of said axle structure, one of saiddevices at each side being forwardly and the other being rearwardly ofthe axle and each device having a pressure chamber provided with amovable wall; conduit means opening into the pressure chambers of eachpair of said devices and including valve means for each pair of devicescontrolling the ow of pressure iluid thereto; means for independentlyactuating said valves to supply pressure uid to the pressure charnbersof respective pairs of said devices upon a predetermined movement ofsaid frame and axle structures toward each other to therebysimultaneously actuate said movable walls, and means operativelyassociated with said movable wall to provide supplementalpneumatic-cushioning means between said devices and said frame whenpressurized air is supplied to said pressure chambers.

13. ln vehicle-suspension means: a frame structure; an axle structure;spring means normally supporting said frame structure on said axlestructure, normally non-load supporting pneumatic means at each side ofone of said frame and axle structures and operably attached thereto toprovide, when energized auxiliary, pneumatic load supportinginterconnection means between said structures, said auxiliary pneumaticinterconnection means normally being disconnected from one of saidstructures, each said pneumatic means comprising afluid-pressureoperated device forwardly and rearwardly respectively ofsaid axle structure; and respective pneumatic control means for eachpneumatic means, said pneumatic control means having parts operablydisposed between said frame and axle structures and engageable uponpredetermined relative movement of said axle and frame structures atrespective sides thereof toward each other and including means operablewhen engaged to eiect energization of said pneumatic means to rendersame effective only upon said predetermined relative movement to provideauxiliary pneumatic suspension of the frame structure.

14. The invention defined by claim 13 including manually-operable meansfor rendering the pneumatic means inoperable.

References Cited in the le of this patent UNITED STATES PATENTS1,244,752 McCrosson Oct. 30, 1917 1,278,350 Hubbard Sept. 10, 1918`1,974,171 Bizzarri Sept. 18, 1934 2,257,913 Maranville Oct. 7, 19412,361,575 Thompson Oct. 31, 1944 2,864,454 La Bene Dec. 16, s 2,903,256Weiss Sept. 8, 1959 2,945,702 Winkelmann July 19, 1960 FOREIGN PATENTS12014780 Germany -..-.-.-.-.i..., July 272 1957

